一、前言

　　關(guān)于EnableCaching最簡單使用，個人感覺只需提供一個CacheManager的一個實例就好了。springboot為我們提供了cache相關(guān)的自動配置。引入cache模塊，如下。

二、maven依賴

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-cache</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><dependency><groupId>org.springframework.integration</groupId><artifactId>spring-integration-redis</artifactId></dependency><dependency><groupId>redis.clients</groupId><artifactId>jedis</artifactId></dependency>

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三、緩存類型

?　　本人也僅僅使用了redis、guava、ehcache。更多詳情請參考 spring cache官方文檔。

https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-caching.html

四、常用注解

　　@Cacheable????觸發(fā)緩存填充

　　@CacheEvict????觸發(fā)緩存驅(qū)逐

　　@CachePut????更新緩存而不會干擾方法執(zhí)行

　　@Caching????重新組合要在方法上應(yīng)用的多個緩存操作

　　@CacheConfig????在類級別共享一些常見的緩存相關(guān)設(shè)置

五、Spring Cache提供的SpEL上下文數(shù)據(jù)

　　下表直接摘自Spring官方文檔：

名字	位置	描述	示例
methodName	root對象	當(dāng)前被調(diào)用的方法名	#root.methodName
method	root對象	當(dāng)前被調(diào)用的方法	#root.method.name
target	root對象	當(dāng)前被調(diào)用的目標(biāo)對象	#root.target
targetClass	root對象	當(dāng)前被調(diào)用的目標(biāo)對象類	#root.targetClass
args	root對象	當(dāng)前被調(diào)用的方法的參數(shù)列表	#root.args[0]
caches	root對象	當(dāng)前方法調(diào)用使用的緩存列表（如@Cacheable(value={"cache1", "cache2"})），則有兩個cache	#root.caches[0].name
argument name	執(zhí)行上下文	當(dāng)前被調(diào)用的方法的參數(shù)，如findById(Long id)，我們可以通過#id拿到參數(shù)	#user.id
result	執(zhí)行上下文	方法執(zhí)行后的返回值（僅當(dāng)方法執(zhí)行之后的判斷有效，如‘unless’，'cache evict'的beforeInvocation=false）	#result

?六、RedisCacheManager配置

　　基于jedis

@Configuration
@EnableCaching public class RedisCacheConfig extends CachingConfigurerSupport {@Autowiredprivate RedisProperties redisProperties;@Beanpublic JedisConnectionFactory jedisConnectionFactory() {// 獲取服務(wù)器數(shù)組(這里要相信自己的輸入，所以沒有考慮空指針問題)String[] serverArray = redisProperties.getClusterNodes().split(",");RedisClusterConfiguration redisClusterConfiguration = new RedisClusterConfiguration(Arrays.asList(serverArray));JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();// 最大空閑連接數(shù), 默認(rèn)8個jedisPoolConfig.setMaxIdle(100);// 最大連接數(shù), 默認(rèn)8個jedisPoolConfig.setMaxTotal(500);// 最小空閑連接數(shù), 默認(rèn)0jedisPoolConfig.setMinIdle(0);// 獲取連接時的最大等待毫秒數(shù)(如果設(shè)置為阻塞時BlockWhenExhausted),如果超時就拋異常, 小于零:阻塞不確定的時間,// 默認(rèn)-1jedisPoolConfig.setMaxWaitMillis(2000); // 設(shè)置2秒// 對拿到的connection進行validateObject校驗jedisPoolConfig.setTestOnBorrow(true);return new JedisConnectionFactory(redisClusterConfiguration,jedisPoolConfig);}/** * 注入redis template * * @return */@Bean@Qualifier("redisTemplate")public RedisTemplate redisTemplate(JedisConnectionFactoryjedisConnectionFactory, Jackson2JsonRedisSerializer jackson2JsonRedisSerializer) {RedisTemplate template = new RedisTemplate();template.setConnectionFactory(jedisConnectionFactory);template.setKeySerializer(new JdkSerializationRedisSerializer());template.setValueSerializer(jackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}/** * redis cache manager * * @return */@Bean@Primarypublic RedisCacheManager redisCacheManager(JedisConnectionFactory jedisConnectionFactory, ObjectProvider<List<RedisCacheConfigurationProvider>> configurationProvider) {Map<String, RedisCacheConfiguration> redisCacheConfigurationMap = Maps.newHashMap();List<RedisCacheConfigurationProvider> configurations= configurationProvider.getIfAvailable();if (!CollectionUtils.isEmpty(configurations)) {for (RedisCacheConfigurationProvider configuration : configurations) {redisCacheConfigurationMap.putAll(configuration.resolve());}}RedisCacheManager cacheManager = RedisCacheManager.RedisCacheManagerBuilder.fromConnectionFactory(jedisConnectionFactory).cacheDefaults(resovleRedisCacheConfiguration(Duration.ofSeconds(300), JacksonHelper.genJavaType(Object.class))).withInitialCacheConfigurations(redisCacheConfigurationMap).build();return cacheManager;}private static RedisCacheConfiguration resovleRedisCacheConfiguration(Duration duration, JavaType javaType) {return RedisCacheConfiguration.defaultCacheConfig().serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer())).serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new Jackson2JsonRedisSerializer<>(javaType))).entryTtl(duration);}/** * 配置一個序列器, 將對象序列化為字符串存儲, 和將對象反序列化為對象 */@Beanpublic Jackson2JsonRedisSerializer jackson2JsonRedisSerializer() {Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);ObjectMapper om = new ObjectMapper();om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);jackson2JsonRedisSerializer.setObjectMapper(om);return jackson2JsonRedisSerializer;}public static abstract class RedisCacheConfigurationProvider {// key = 緩存名稱， value = 緩存時間 和 緩存類型protected Map<String, Pair<Duration, JavaType>> configs;protected abstract void initConfigs();public Map<String, RedisCacheConfiguration> resolve() {initConfigs();Assert.notEmpty(configs, "RedisCacheConfigurationProvider 配置不能為空...");Map<String, RedisCacheConfiguration> result = Maps.newHashMap();configs.forEach((cacheName, pair) -> result.put(cacheName, resovleRedisCacheConfiguration(pair.getKey(), pair.getValue())));return result;}}}

　　基于Lettuce

@Configuration @EnableCaching public class RedisCacheConfig extends CachingConfigurerSupport {@Autowiredprivate RedisProperties redisProperties;@Beanpublic LettuceConnectionFactory lettuceConnectionFactory() {String[] serverArray = redisProperties.getClusterNodes().split(",");// 獲取服務(wù)器數(shù)組(這里要相信自己的輸入，所以沒有考慮空指針問題)RedisClusterConfiguration redisClusterConfiguration = new RedisClusterConfiguration(Arrays.asList(serverArray));GenericObjectPoolConfig poolConfig = new GenericObjectPoolConfig();// 最大空閑連接數(shù), 默認(rèn)8個poolConfig.setMaxIdle(100);// 最大連接數(shù), 默認(rèn)8個poolConfig.setMaxTotal(500);// 最小空閑連接數(shù), 默認(rèn)0poolConfig.setMinIdle(0);LettuceClientConfiguration lettuceClientConfiguration = LettucePoolingClientConfiguration.builder().commandTimeout(Duration.ofSeconds(15)).poolConfig(poolConfig).shutdownTimeout(Duration.ZERO).build();return new LettuceConnectionFactory(redisClusterConfiguration, lettuceClientConfiguration);}/** * 注入redis template * * @return */@Bean@Qualifier("redisTemplate")public RedisTemplate redisTemplate(LettuceConnectionFactory lettuceConnectionFactory, Jackson2JsonRedisSerializer jackson2JsonRedisSerializer) {RedisTemplate template = new RedisTemplate();template.setConnectionFactory(lettuceConnectionFactory);template.setKeySerializer(new JdkSerializationRedisSerializer());template.setValueSerializer(jackson2JsonRedisSerializer);template.afterPropertiesSet();return template;}/** * redis cache manager * * @return */@Bean@Primarypublic RedisCacheManager redisCacheManager(LettuceConnectionFactory lettuceConnectionFactory, ObjectProvider<List<RedisCacheConfigurationProvider>> configurationProvider) {Map<String, RedisCacheConfiguration> redisCacheConfigurationMap = Maps.newHashMap();List<RedisCacheConfigurationProvider> configurations = configurationProvider.getIfAvailable();if (!CollectionUtils.isEmpty(configurations)) {for (RedisCacheConfigurationProvider configuration : configurations) {redisCacheConfigurationMap.putAll(configuration.resolve());}}RedisCacheManager cacheManager = RedisCacheManager.RedisCacheManagerBuilder.fromConnectionFactory(lettuceConnectionFactory).cacheDefaults(resovleRedisCacheConfiguration(Duration.ofSeconds(300), JacksonHelper.genJavaType(Object.class))).withInitialCacheConfigurations(redisCacheConfigurationMap).build();return cacheManager;}private static RedisCacheConfiguration resovleRedisCacheConfiguration(Duration duration, JavaType javaType) {return RedisCacheConfiguration.defaultCacheConfig().serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer())).serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new Jackson2JsonRedisSerializer<>(javaType))).entryTtl(duration);}@Beanpublic RedisLockRegistry redisLockRegistry(LettuceConnectionFactory lettuceConnectionFactory) {return new RedisLockRegistry(lettuceConnectionFactory, "recharge-plateform", 60000 * 20);}/** * 配置一個序列器, 將對象序列化為字符串存儲, 和將對象反序列化為對象 */@Beanpublic Jackson2JsonRedisSerializer jackson2JsonRedisSerializer() {Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);ObjectMapper om = new ObjectMapper();om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);jackson2JsonRedisSerializer.setObjectMapper(om);return jackson2JsonRedisSerializer;}public static abstract class RedisCacheConfigurationProvider {// key = 緩存名稱， value = 緩存時間 和 緩存類型protected Map<String, Pair<Duration, JavaType>> configs;protected abstract void initConfigs();public Map<String, RedisCacheConfiguration> resolve() {initConfigs();Assert.notEmpty(configs, "RedisCacheConfigurationProvider 配置不能為空...");Map<String, RedisCacheConfiguration> result = Maps.newHashMap();configs.forEach((cacheName, pair) -> result.put(cacheName, resovleRedisCacheConfiguration(pair.getKey(), pair.getValue())));return result;}}}

　　Jedis和Lettuce比較

　　Jedis 是直連模式，在多個線程間共享一個 Jedis 實例時是線程不安全的，如果想要在多線程環(huán)境下使用 Jedis，需要使用連接池，

　　每個線程都去拿自己的 Jedis 實例，當(dāng)連接數(shù)量增多時，物理連接成本就較高了。

?

　　Lettuce的連接是基于Netty的，連接實例可以在多個線程間共享，

　　所以，一個多線程的應(yīng)用可以使用同一個連接實例，而不用擔(dān)心并發(fā)線程的數(shù)量。當(dāng)然這個也是可伸縮的設(shè)計，一個連接實例不夠的情況也可以按需增加連接實例。通過異步的方式可以讓我們更好的利用系統(tǒng)資源，而不用浪費線程等待網(wǎng)絡(luò)或磁盤I/O。

　　

　　只在基于Lettuce的配置中，加入了RedisLockRegistry對應(yīng)bean的配置，由于在集群的模式下，基于Jedis的配置下，通過RedisLockRegistry 獲取分布式鎖的時候報錯：

EvalSha is not supported in cluster environment

　　具體的解決方案就是切換至基于Lettuce的配置，請參考

https://stackoverflow.com/questions/47092475/spring-boot-redistemplate-execute-sc

　　

　　RedisCacheConfigurationProvider 作用為不同的cache提供特定的緩存時間以及key、value序列化和反序列化的方式。具體使用方式如下。

@Componentpublic class CouponRedisCacheConfigurationProvider extends RedisCacheConfig.RedisCacheConfigurationProvider {@Overrideprotected void initConfigs() {this.configs = Maps.newHashMap();this.configs.put(CouponConstants.COUPON_ALL_CACHE, new Pair<>(Duration.ofHours(1), JacksonHelper.genMapType(HashMap.class, Integer.class, Coupon.class)));this.configs.put(CouponConstants.COUPON_GOOD_CACHE, new Pair<>(Duration.ofHours(1), JacksonHelper.genCollectionType(List.class, String.class)));this.configs.put(CouponConstants.COUPON_HANDLE_TELEPHONE_STATUS_CACHE, new Pair<>(Duration.ofMinutes(10), JacksonHelper.genCollectionType(List.class, CouponHandle.class)));this.configs.put(CouponConstants.COUPON_HANDLE_TELEPHONE_GOOD_CACHE, new Pair<>(Duration.ofMinutes(10), JacksonHelper.genCollectionType(List.class, CouponHandle.class)));}}

　　JacksonHelper 作用是根據(jù)不同的類型的對象獲取對應(yīng)的JavaType對象，在構(gòu)造RedisTempalte序列化和反序列化器Jackson2JsonRedisSerializer對象需要。具體代碼如下。

public class JacksonHelper {private static Logger LOGGER = LoggerFactory.getLogger(JacksonHelper.class);private static final SimpleModule module = initModule();private static final ObjectMapper objectMapper;private static final ObjectMapper prettyMapper;public JacksonHelper() {}private static SimpleModule initModule() {return (new SimpleModule()).addSerializer(BigDecimal.class, new BigDecimalSerializer()).addSerializer(LocalTime.class, new LocalTimeSerializer()).addDeserializer(LocalTime.class, new LocalTimeDeserializer()).addSerializer(LocalDate.class, new LocalDateSerializer()).addDeserializer(LocalDate.class, new LocalDateDeserializer()).addSerializer(LocalDateTime.class, new LocalDateTimeSerializer()).addDeserializer(LocalDateTime.class, new LocalDateTimeDeserializer()).addSerializer(Date.class, new DateSerializer()).addDeserializer(Date.class, new DateDeserializer());}public static JavaType genJavaType(TypeReference<?> typeReference) {return getObjectMapper().getTypeFactory().constructType(typeReference.getType());}public static JavaType genJavaType(Class<?> clazz) {return getObjectMapper().getTypeFactory().constructType(clazz);}public static JavaType genCollectionType(Class<? extends Collection> collectionClazz, Class<?> javaClazz) {return getObjectMapper().getTypeFactory().constructCollectionType(collectionClazz, javaClazz);}public static JavaType genMapType(Class<? extends Map> mapClazz, Class<?> keyClass, Class<?> valueClazz) {return getObjectMapper().getTypeFactory().constructMapType(mapClazz, keyClass, valueClazz);}public static ObjectMapper getObjectMapper() {return objectMapper;}public static ObjectMapper getPrettyMapper() {return prettyMapper;}static {objectMapper = (new ObjectMapper()).registerModule(module).configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false).configure(DeserializationFeature.READ_UNKNOWN_ENUM_VALUES_AS_NULL, true).configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);prettyMapper = objectMapper.copy().configure(SerializationFeature.INDENT_OUTPUT, true);}}class LocalDateDeserializer extends JsonDeserializer<LocalDate> {public LocalDateDeserializer() {}public LocalDate deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {String dateString = ((JsonNode) jp.getCodec().readTree(jp)).asText();return LocalDate.parse(dateString, DateTimeFormatter.ISO_LOCAL_DATE);}}class DateDeserializer extends JsonDeserializer<Date> {public DateDeserializer() {}public Date deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {String dateTimeStr = ((JsonNode) jp.getCodec().readTree(jp)).asText();SimpleDateFormat sdf = new SimpleDateFormat(CouponConstants.DATE_TIME_FORMATER);ParsePosition pos = new ParsePosition(0);return sdf.parse(dateTimeStr, pos);}}class LocalDateTimeDeserializer extends JsonDeserializer<LocalDateTime> {public LocalDateTimeDeserializer() {}public LocalDateTime deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {String dateTimeStr = ((JsonNode) jp.getCodec().readTree(jp)).asText();return LocalDateTime.parse(dateTimeStr, DateTimeFormatter.ISO_LOCAL_DATE_TIME);}}class LocalTimeDeserializer extends JsonDeserializer<LocalTime> {public LocalTimeDeserializer() {}public LocalTime deserialize(JsonParser jp, DeserializationContext ctxt) throws IOException {String dateString = ((JsonNode) jp.getCodec().readTree(jp)).asText();return LocalTime.parse(dateString, DateTimeFormatter.ISO_LOCAL_TIME);}}class BigDecimalSerializer extends JsonSerializer<BigDecimal> {public BigDecimalSerializer() {}public void serialize(BigDecimal value, JsonGenerator jgen, SerializerProvider provider) throws IOException {jgen.writeString(value.toString());}}class LocalDateSerializer extends JsonSerializer<LocalDate> {public LocalDateSerializer() {}public void serialize(LocalDate value, JsonGenerator jgen, SerializerProvider provider) throws IOException {jgen.writeString(DateTimeFormatter.ISO_LOCAL_DATE.format(value));}}class LocalDateTimeSerializer extends JsonSerializer<LocalDateTime> {public LocalDateTimeSerializer() {}public void serialize(LocalDateTime value, JsonGenerator jgen, SerializerProvider provider) throws IOException {jgen.writeString(DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value));}}class DateSerializer extends JsonSerializer<Date> {public DateSerializer() {}public void serialize(Date value, JsonGenerator jgen, SerializerProvider provider) throws IOException {SimpleDateFormat sdf = new SimpleDateFormat(CouponConstants.DATE_TIME_FORMATER);jgen.writeString(sdf.format(value));}}class LocalTimeSerializer extends JsonSerializer<LocalTime> {public LocalTimeSerializer() {}public void serialize(LocalTime value, JsonGenerator jgen, SerializerProvider provider) throws IOException {jgen.writeString(DateTimeFormatter.ISO_LOCAL_TIME.format(value));}}

　　業(yè)務(wù)代碼

@Component public class ServiceImpl { @Override@CacheEvict(cacheNames = CouponConstants.COUPON_HANDLE_TELEPHONE_STATUS_CACHE, key = "#telephone+'#'+#status", beforeInvocation = true)public void evictCouponHandles(String telephone, Integer status) {}@Override@Cacheable(cacheNames = CouponConstants.COUPON_HANDLE_TELEPHONE_STATUS_CACHE, key = "#telephone+'#'+#status", sync = true)public List<CouponHandle> searchCouponHandles(String telephone, Integer status) {}}

　　不同的緩存對應(yīng)不同的存儲類型，不同的存儲類型對應(yīng)著不同的序列化和反序列化器，這就保證了再調(diào)用注有@Cacheable注解的代碼時獲取到的對象不會發(fā)生類型轉(zhuǎn)換錯誤。關(guān)于設(shè)置不同的cache下過期時間以及序列化和反序列器，請參考下面更直接明了的例子。

@Configurationpublic class RedisCacheConfig {@Beanpublic KeyGenerator simpleKeyGenerator() {return (o, method, objects) -> {StringBuilder stringBuilder = new StringBuilder();stringBuilder.append(o.getClass().getSimpleName());stringBuilder.append(".");stringBuilder.append(method.getName());stringBuilder.append("[");for (Object obj : objects) {stringBuilder.append(obj.toString());}stringBuilder.append("]");return stringBuilder.toString();};}@Beanpublic CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {return new RedisCacheManager(RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory),this.getRedisCacheConfigurationWithTtl(600), // 默認(rèn)策略，未配置的 cache 會使用這個this.getRedisCacheConfigurationMap() // 指定 cache 策略 );}private Map<String, RedisCacheConfiguration> getRedisCacheConfigurationMap() {Map<String, RedisCacheConfiguration> redisCacheConfigurationMap = new HashMap<>();redisCacheConfigurationMap.put("UserInfoList", this.getRedisCacheConfigurationWithTtl(3000));redisCacheConfigurationMap.put("UserInfoListAnother", this.getRedisCacheConfigurationWithTtl(18000));return redisCacheConfigurationMap;}private RedisCacheConfiguration getRedisCacheConfigurationWithTtl(Integer seconds) {Jackson2JsonRedisSerializer<Object> jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer<>(Object.class);ObjectMapper om = new ObjectMapper();om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);jackson2JsonRedisSerializer.setObjectMapper(om);RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();redisCacheConfiguration = redisCacheConfiguration.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer)).entryTtl(Duration.ofSeconds(seconds));return redisCacheConfiguration;}} @Cacheable(value = "UserInfoList", keyGenerator = "simpleKeyGenerator") // 3000秒 @Cacheable(value = "UserInfoListAnother", keyGenerator = "simpleKeyGenerator") // 18000秒 @Cacheable(value = "DefaultKeyTest", keyGenerator = "simpleKeyGenerator") // 600秒，未指定的cache，使用默認(rèn)策略

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轉(zhuǎn)載于:https://www.cnblogs.com/hujunzheng/p/9660681.html

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